Question

What is meant by the least count (LC) of a measuring instrument?

Answer 1

It is the smallest and accurate value measured by an instrument. Every instrument measures the value for which it is made and it has a specific minimum observation value. Every student should see various instruments in the laboratory and know the least count.

Complete step by step solution:
The least count of a measuring instrument is the smallest and accurate value in the measured quantity that can be resolved on the desired instrument scale. It is related to the precision of an instrument, an instrument that can measure the smallest “Least Count” value. Any instrument cannot measure the value lesser than the least count.

The least count of an instrument is inversely proportional to the precision of the instrument. The least count of an instrument is one of the very important tools in order to get accurate readings of instruments like the Vernier Caliper and screw gauge used in various experiments. Suppose the least count of a micrometer is given as 0.01 mm, below that we cannot measure the length.
Example: Least count of Vernier Caliper is 0.1 mm. and 0.01 mm of a micrometer.

Note: If the least count of Vernier is 0.1mm means Vernier can’t measure the value less than the 0.1mm. The minimum is the value of the least count the maximum is the accuracy in observation value by the instrument. Some other examples are microscopes which can measure the value starting from. The devices which are made with the least count are used for measuring microscopic objects like various dust partials, pathogens and other bacteria.